Limited-pressure feed device



Sept.V 9, 1930. c. s. BURTON LIMITED PRESSURE FEED DEVICE 2 Sheets-Sheetl Filed March 31, 1923 Sept. 9, 1930. c, s, BuRroN 1,775,506

` LIMITED PRESSURE FEED DEVICE Filed March :51, '192s z sheets-snee: 2

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r I I Patented Sept. 9, 1930 UNITED STATES PATENT OFFICE CHARLES S.BURTON, OF OAK PARK, ILLINOIS, ASSIGNOR TO STEWART-WARNER COR- PORATION,OF CHICAGO, ILLINOIS, A. CORPORATION OF VIRGINIA.

LIMITED-PRESSURE FEED DEVICE Application led March 31, 1923. Serial No.628,951.

The purpose of this invention is to provide an improved construction forsupplying liquid fuel to an internal combustion engine from a mainsupply tank situated at a lower level than the carbureter intake. Itconsists in the elements and features of construction shown anddescribed as indicated in the claims.

In the drawings Figure 1 is a diagrammatic view of the nature of a sideelevation of an automobile having its engine equipped with thisinvention, showing the relative position of the several elements which(2o-operate in the fuel feeding.

Figure 2 is a vertical fore-and-aft section of the main fuelv supplytank, and specifically of the fuel feeding device which is intrudedthereinto, the tank and said device being broken away to reduce thevertical extent of the figure.

Figure 3 is a plan view of an air-pumping device operated by alternatingpressure and suction derived from one cylinder of the engine fordeveloping the airpressure by which the fuel elevating device shown inFigure 2 is operated. f

Figure 4 is a section at the line, 4-4, on Figure 3.

Figure 5 is a detail section at the line 5 5, on Figure 3.

Figure 6 is a side elevation of the liquid pumping device which isintruded into theV main fuel tank.

Figure 7 is a top plan View of the same. Figure 8 is a section at theline 8-8, on Figure 6.

Figure Figure 2.

Figure 10 is a section at the line, 10-10, on Figure 7.

9 .is a section at the line 9-9, on

Figure 11 1s a vertical section of a suction` force pumping device whichmay be employed for fuel feeding, being immersed in the main fuel tankand connected with the air pumping device operated by engine connection.

Figure 12 is a detail vertical section showing a standpipe on the fuelfeed line near the' carbureter.

Figure 13 is a detail sectional view showing a modification of theconstruction as appearing at the horizontal plane of the axis of aturn-cock, corresponding to turncock 41, seen in Figure 4.

Figure 14 is a detail section of a check valve evice which may beinterposed from the pipe line of the engine for a certain function. Inthe construction shown in the drawings the automobile engine isindicated at A; the main fuel supply tank is indicated at B; C indicatesin general an air-compressing pump device connected at one side with onecylinder of the engine, and at the other side with the liquid pumpingdevice in the main tank. D indicates in general and in its totality theliquid pumping device in the main tank. 4

The air-compressing pump operated by the alternation of suction andpressure derived from one cylinder of the engine will be firstdescribed. This device consists of a cast f1tting, l, which has a duct,2, for connection at the intake end by means of a pipe, 3, with onecylinder of the engine, the connection of the pipe with the fittingbeing made in any convenient manner, being shown in a familiar manneremploying a compression coupling, 4. This duct entering horizontally isdeflected at right angles and terminates through thedownwardly-projecting nipple, 5, which is constructed for coupling tothe upper end of a U-tube, 6, preferably of glass, and coupled by meansof the stuiing box coupling, 7 The other end of this U-tube is similarlycoupled to a second downwardly-projecting nipple, 8, of the fitting, 1.In this nipple and the horizontally-extending adjacent end of 'thetting, there is formed an air discharge duct comprising the portion, 9,extending vertically in the nipple, 8, a valve chamber, 10, at the upperend of said ,duct portion, 9, and a horizontally-extending portion, 11,leading to the said adjacent end of the fitting, 1, into which iscoupled the pressure pipe, 12, which leads to the liquid pumping devicein the main tank. In the valve chamber, 10, there. is a check valve, 13,seat-ing downwardly for closing the duct, 9, against return flowtowardthe U tube, 6.' Leading oiil horizontally and laterally from theduct, 9, at a point below the seat of the valve, 13, there is a duct,15, which leads to a valve chamber, 16, from which a duct, 17 leads tothe atmosphere. A check valve, 18, in this valve chamber, 16, seatsdownwardly to prevent discharge and permit intake of air through theterminal duct, 17. 19 and 20 are plugs screwed into tapped holes boredto form the valve chambers, 10 and 16. In line with the duct, 11, andextending in the opposite direction from the valve chamber,'10, is aduct 22, which connects with a vertically-extending duct, 23, to beclosed by a valve, 24, held yielding/ly to its seat, 23, by a spring,25, coiled around the stem, 26, of said valve stopped at the lower endon the valve, and at the upper end upon a tension-adjusting screw, 27,screwed into the standard, 28, eX- tending up from the upper side of thefitting, C. As illustrated, the duct, 22, the valve seat, 23, andstandard, 28, are provided by a unitary fitting screwed into a tappedbore in the upper side of the main fitting, C. As illustrated, also, theduct, 23, has connection with the duct, 2, leading from the engine,l

said connection being controlled by a turn- A cock, 110, which may beset to connect the rellef duct 23, alternatively either with the duct,11, or with the duct, 2, for a purpose hereinafter described.

The U tube, 6, is occupied by a suitable liquid, preferably mercury, tooperate as a liquid piston which shall reciprocate in the tu eresponsive -to the alternating pressure and suction derived from theengine through the ipe, 3, and duct, 2. Preferably there are oated uponthe upper ends of the liquid piston, 30, cork loat valves, 31, and 32,for seating at the lower ends of the ducts, 2 and 9, respectively, andstopping the' thrust of the liquid piston in its movement responsiverespectively to the suction and pressure. 'Desirably these cork oatvalves are each provided with a pendant weight or tang, 33,

i which may be a screw screwed into the cork and serving both forholding the oat in true vert1cal position and also for giving the liquidplston frictional or capillary grasp upon the float valve to insure thelatter moving with the surface of the liquid piston.

.Upon considering this air pumping device, it will be understoodV thatin the suction phase of the cycle of the engine cylinder with which thedevice is connected, the liquid plston will be actuated forreciprocation upward at the end toward the engine connection. causingair to be drawn in at the air intake, 17, past the check valve, 18, andthat upon the pressure phase of said engine cycle 4 the liquid pistonwill be driven in the opposite direction, thrusting upward its endremote from the engine connection and driving out the air past the checkvalve, 13, and out through the pipe, 12, leading to the liquidpumpingdevice in the main tank; and it will l be seen that at each successivereciprocation of the piston in the engine cylinder which is thusconnected, additional air will be driven through the pipe, 12, and thateventually pressure will be accumulated in the liquid-pumping device toany desired degree -up to the maximum pressure aiforded by the adjustedto limit the l pressure produced toL any desired degree by adjusting thetension screw, 27.

As thus far described, this air pumping device is designed and adaptedto co-operate with a liquid-pumping device in the main tank of acharacter to be operated by continuous air pressure on the liquid in achamber having connection for discharge of liquid toward the carbureter.'If it is desired to supply the fuel to the carbureter by any ordinarysuction and force pumping device operated by alternate suction andpressure, the air-pumping device described may be utilized for thispurpose by virtue of a by-pass duct, 40, shown in Figure 4, connectingthe ducts, 9 and 11, by-passing the valve, 13, and causing the alternatesuction and pressure operating at the engine side of the liquid pistonto produce similarly alternating suction and pressure in the pipe, 11,'which will be connected to a simple suction-and-force-pump devicehereinafter described, submerged in the lfuel supply in the main tank. Ashutoif valve or turn-cock, 41, controls the bypass duct, 40, and willbe closed when the device is operated in the manner first abovedescribed for producing continuous air pressure through the pipe, 12,and opened only when the device is employed in the last described mannerfor operating a simplel suction and force pump device in the tank. Whenit is thus employed, it will be understood that the check-valve, 16,will be forced to its seat by screwing in the plug, 20, so as to preventthe suction from being satisfied by direct air inlet and so failing tooperate in the line leading to the suction and force pump.

Figure 13 shows a modification dispensing with attention to the plug,20, as described, when the turn-cock, 41, is opened, said modificationconsisting in leading oif the duct, 15, in a direction to intersect theaxis of the turn-cock, which is then extended soas to Dfi control saidduct, 15, the turn-cock having a port, 41a, which registers with theduct, 15, at one position of the turn-cock, permitting air intake whenthe turn-cock is at closed position as to the by-pass, 40, and closingthe duct, 15, when said by-pass is opened.

Theliquid pumping device in the main tank of a character to co-operatewith the air pumping device above described when operating as firstabove described, comprises a cast fitting, 50, adapted to be inserted inand mounted at an aperture, b, in the top of the tank, B. Said fittinghas a nipple, 51, for connection with the air pipe line 12, leading fromthe air pumping device, and a nipple, 52, for connection with the fuelpipe line, leading to the carbureter. The nipple, 52, receives, thrustdown through it, the terminal portion ofthe fuel pipe line, 54, whichleads to the carbureter, the said pipe terminal be-` ing connectedliquid-tight at said nipple by means of a familiar form of compressioncoupling, 55, shown in the drawings. This pipe terminal extends downwithin a larger passage or chamber, 56, partly formed in a boss,

50g, extending from the lower side of the fitting, 50, and partly formedby means of a pipe, 57, screwed into said boss and extending down in thefuel tank to near the bottom thereof for connection at its lower end tothe second cast fitting, 60, hereinafter more particularly described.The nipple, 51, receives the terminal portion of the air pipe line, 12,said terminal being inserted liquid-tight through said nipple andsecured thereto by a compression coupling, 58, from the nipple mouth, aduct, 51a, extends down in an extension 50f, at the left hand side ofthe boss, 50g, as seen in Fig. 2 and Fig. 9, and connects with ahorizontal duct, 82, from the other end of which a duct, 84, leads downthrough a downwardly-projecting nipple and coupling, 59a, which isconnected by a pipe, 59, with an 11p-turned nipple, 62, of the fitting,60, the connection of said pipe, 59, at both ends with said nipplesrespectively, being made by compression couplings, 59a, 59h, the pipebeing of sufficient length to intrude at its opposite ends into the twonipples loosely enough so that it may be introduced into one of them atthe slightly oblique angle made necessary by its length and the presenceat the other end of the other nipple, and thrust into the firstmentioned nipple far enough to permit it to be swung over into line withthe `two nipples and retracted into the second nipple, preparatory totightening the compression couplings. The nipple, 62, is connected by across duct, 63, with an upwardlyprojecting nozzle, 64, which is situatedcentrally with respect to a hollow boss, 65, to which the lower end ofthe pipe, 57, is screwed. Thisyhollow boss has its cavity in what may betermed hour-glass form for constituting a Venturi tube, and is aperturedaround the base of the nozzle, 64, for inlet of liquidjuel from the tankinto said Venturi tube.

Upon considering this construction, it will be seen that the nozzle, 64,is in continuous connection with the air pipe line, 11, so thatcompressed air delivered through said pipe, 11, is discharged upwardlyin a jet from the nozzle, 64, within the Venturi tube and will therebyact upon the liquid for driving it upward within the chamber formed bythe pipe, 57, and passage, 56, in the hollow boss, 50, of the fitting,50, the air acting partly 'as a piston behind the liquid, and partly foraerating the liquid to some extent. .The air which penetrates and actsfor aerating the liquid tends to escape, and does escape, to a largeextent in the upper part of said chamber, 56, which upward from thelower end of the pipe, 54, constitutes an air trap, the air whichbecomes separated from the liquid in this trap being still under a veryconsiderable degree of compression, but operating with less pressureupon the liquidbelow it than is produced by the more' highly compressedair delivered from the nozzle in the venturi. The co-operation of thecompressed air in the trap and the driving action of the more highlycompressed air jet from the nozzle, forces the liquid up through thepipe, 54, and on to the carbureter. At any convenient point in thisliquid pipe line, there may be interposed a check valve to preventbackflow of the liquid. Such check Valve x is shown and is prefera-blylocated at the foot of a little standpipe, 70, which is erected on thepipe-line, 54,

immediately in front of the dash for a specific function hereinaftermentioned.

Obviously in the absence of provision for preventing it, there willoccur an accumulation of compressed air escaped from the liquid fuel inthe air trap portion of the chamber 56, formed by the pipe, 57, and thecavity, of the fitting, 50, which accumulation would eventually in theabsence of preventing means, occupy the entire trap space and extenddown to the intake end of the pipe, 54, and would then escape throughsaid pipe, with the undesirable result of aeratingthe liquid fuel whichi-s being fed into the carbureter. It is necessary, therefore, toprovide for venting this air trap at a pressure limited so that the sameshall not find its vent through the pipe, 54, as mentioned. For thispurpose the fitting, 50, has an extension to the right hand as seen at50% Figure 9, through which there is formed a duct, 50", communicatingat its left hand end with the upper portion of the air trap, 56; andintersecting this duct, 50h, there is-made a vertical bore, 50",counterbored from the upper end as seen at 50y forming anupwardly-facing valve seat, 50, and a valve, 50d, is provided seating onsaid seat having its stem extending up through a guide and spring-tensioning plug, 50e, screwed into the upper Counterbored end of theboss, 50a, for stopping the upper end of the spring. This plug ortension screw may be screwed down to tension the spring 50, to anydesired degree so that pressure in the air trap chamber beyond thatdegree will open the'valve and permit the escape of air out through theboss which is laterally apertured at 50m, into the main fuel tank.Notwithstanding the air pumping device above described may be providedwith the safety ventvalve for limiting the air pressure which can bedeveloped by said device, it will be found advantageous to provide asimilar airpressure-limiting safety valve on the liquid pumping devicein the tank, and such airpressure-limiting safety valve is shown at 84,seating on a seat, 81, provided in the duct, 84, which extends up fromthe connection therewith of the horizontal cross duct, 82, and iscounterbored at 83, in forming said valve seat 81 to form a valvechamber and spring chamber there-above for the valve, 84a, and thespring, 85, coiled |about the valve stem 84W and reacting between saidvalve and the tensioning and valve-stem guide-screw, 86, screwed intothe upper end of said counterbore. The stem, 84", is fitted-loosely inthe part, 86, for affording air` vent from the chamber, 83. The twopressure-limiting devices above described, one for limiting the pressureand permitting the venting of air from the air trap chamber, and theother for limiting the initial operating pressure from the pressure pipeline, are entirely similar and may be relatively adjusted to each otherto insure the venting of the air trap rbefore thev pressure causes it tovent through the fuel pipe line, and maintaining adequate pressure onthe nozzle for feeding the fuel and upholding the same against thepressure in the trap chamber with adequate excess of pressure above thelatter to keep the liquid moving on through the fuel pipe line to thecarbureter.

It will be found convenient for maintaining uniform pressure on thecarbureter to provide the little standpipe, 70, above mentioned, erectedon the fuel pipe line extending to a height sufficiently above thecarbureter to afford adequate gravity head for feeding the carbureter.This standpipe may have capacity for supplying the carbureter throughany short interval of interruption in the feeding operation of thedevices described which may occur from any cause; and to prevent theliabilityof overflowing this standpipe, it is capped at the upper end,and the cap, 71, is provided with a small vent aperture, 72, which isclosed by a little cork, 7 3, which floats upon the top of the liquid inthe standpipe and is thereby floated upto a seat on the under side ofthe cap, limiting the depth to which the standpipe can fill.

When the air-pumping device described-is to be used for operating asimple suction and force pump for feeding the fuel from the main tank,said suction and force pump device mayy consist of pipe and fittings asshown in Figure 11. The T-fitting 90, has its horizontal cross memberprovided with check valves, 91 and 92, one at each side of theupwardly-extending stem of the T, both opening in the same direction,one end of the cross of the T being connected by an elbow, 93, with thefuel pipe line, 54a, the stem of the T being connected with the air pipeline, 12, through which there is operating alternate suction andpressure due to the closing of the air inlet passage, 17, and the openmgof the by-pass duct, 40.

lIn view of the fact that the vacuum produced by the suction of theengine can never exceed fifteen pounds per square inch, and will seldomexceed twelve pounds, whereas the pressure produced in the pressurephase of the cycle of the cylinder which is connected may be many timesas great, it may be found desirable to provide means for res trictingthe pressure, leaving the suction unrestricted.

This may be accomplished by a simple form of check valve which may beinterposed in the pipe-line, 3, at such -a point as indicated by thedeflection, 100, (see Figure 1), said check valve device beingillustrated in detail in Figure 14, consisting of a small disk, 101,seating downwardly on a horizontal seat provided at the upper end of anelbow, 102, in said pipe connection from the engine, the disk beingchecked as to opening by the opposite elbow Whose lower end has notches,104, dimensioned for affording free movement of air toward the engine inthe suction phase, the disk seating for stoppage of the disk in .theopposite direction during the compression phase, and having a centralaperture, 105, which affords only very restricted path for the gas insaid compression phase.

A preferred method and means of limiting the pressure transmitted fromthe engine without limiting the suction, consists in introducing apressure-relief valve in the line anterior to the liquid piston; and forthis purpose the duct, 23, leading to the pressurelimiting or safetyvalve, 24, is connected as described above, through the turn cock, 110,with the duct, 2. When the turn-cock is set for connecting the ventduct, 23, with the duct, 2, the function, of the safety valve forlimiting the pressure developed beyond the liquid piston is in abeyance,but is rendered unnecessary because that pressure cannot exceed thepressure at the engine side of the liquid piston.

1. In a construction for the purpose indicated, in combination with acontainer constituting a fuel source, a fuel pipe line from the fuelsource for supplying the carbureter of an internal combustion engine, acompressed air conduit discharging within the intake of the fuel pipeline; an air-trapping chamber on the fuel pipe line subsequent to theentrance of the fuel from the fuel source to said pipe line, the pipeline comprising a pipe member which leads on from the airtrappingchamber toward the carbureter opening for fuel intake at the lower partof said air-trapping chamber; whereby the tension of compression in saidtrapping chamber operates for driving the fuel on toward the carbureter,said trapping chamber having a pressure vent at the upper part and ayieldingly seated valve controlling said vent for limiting said tensionof compresslon.

2. In the construction defined in claim 1, the pressure vent openingfrom the trapping chamber being connected for discharge of air withinthe fuel container; whereby vaporized fuel carried by the air may berecovered by condensation in the container.

3. In the construction defined in claim 1,

` foregoing, the pressure vent valve being spring-pressed for seating,and means for ad# justing the tension of the spring to limit at will theair pressure in the system operative for delivery of fuel to thecarbureter.

4. In combination with the construction dened in claim 1, an air pumpingdevice .for furnishing compressed air to the compressed air conduithaving a pressure-limiting vent valve, and adjustable means forresisting its opening.

5. In a construction for the purpose indicated, in combination with acontainer constituting a fuel source, a fuel pipe line from the fuelsource for supplying the carbureter of an internal combustion engine, acompressed air conduit discharging within the intake of the fuel pipeline; an air trapping chamber in the fuel pipe line subsequent to theentrance of the fuel source from said pipe line, the pipe linecomprising a pipe member which' leads on from the air trapping chambertoward the carbureter opening for fuel intake at the lower part of saidair trapping chamber; said :trapping chamber having a pressure vent atthe upper part and a yieldingly seated valve controlling said vent, thefuel pipe line intake in the container being a Venturi tube, and thecompressed air discharge conduit terminating as a nozzle for dischargeof compressed air at the constriction of the venturi.

In testimony whereof, I have hereunto set my hand at Chicago, Illinois,this 28th day of March, 1923.

CHARLES S. BURTON.

